Original 2-1/4" exhaust clamps
 

So here is one I've never really looked into over the years. And came across these in 1 of my old bins that had a lot of very original 1st Gen. Camaro parts. My question would be are these assembly line exhaust clamps. They have a couple of interesting features which are typical of the time period with Oh stamped on the middle of the lower brace, similar to transmission U joint straps and the U bolts have the flat stamping on the top Similar to the original U bolts on the rear ends. Any help would be appreciated. Thanks also with these have flanged nuts or just nuts and lock washers?

I believe they were used in the over axle to cross flow muffler which is a 2.25 they also look like the tailpipe extension clamp for a vette.

Thanks, that's what I thought it was 4 was the crossover pipes.